An electrically powered eraser accepts an elongate circularly cylindrical erasing element between three driving rollers symmetrically arrayed about the erasing element with axes angulated to the axes of the other driving cylinders and to the axis of the erasing element so that the drivin

Apparatus combining the input function of a digitizer and the output function of a plotter to provide a current simultaneous plot of computer input as traditionally provided by a cathode ray tube display is disclosed for computer aided drawing. The apparatus provides a casement having a